Safety lock



Aug. 29, 1933. s M, MERGER 1,925,023

SAFETY LOCK Original Filed Feb. 1927 2 Sheets-Sheet 1 Aug. 29, 1933. 5 MERGER 1,925,023

' SAFETY LOCK Original Filed Feb. 1, 1927 2 Sheets-Sheet 2 l A IIIIIIIIIII Big. 4 14 fi6 Patented Aug. 29, 1933 UNITED STATES 1,925,023 SAFETY LOCK Stanley M. Mercier, Grandview, Ohio, assignor to The Jefirey Manufacturing Company, Columbus, Ohio, a corporation of Ohio Application February 1, 1927, Serial No. 165,226 Renewed March 15, 1932 18 Claims. (c1. 183-82) The present invention relates to certain new and useful improvements in safety locks of the class adapted to prevent reverse rotation of power shafts.

This invention relates particularly to an automatically acting safety lock adapted for association with the head shaft of an elevator of the endless belt and bucket type, to prevent reverse rotation of the head shaft when the actuating' power is interrupted during operation of the Fig. 3 is an end elevation, partly in section andon an enlarged scale, of the safety locking device shown in Figs. 1 and 2.

Fig. 4 is a longitudinal section of the safety locking device shown in Fig. 3.

Like numerals refer to similar parts in they several figures.

In the drawings the numeral 1 refers to the head shaft of an elevator which is supported in.

the journal bearings 2 attached to the supporting timbers 3. Fixed to the head shaft lfis the head wheel 4 of the elevator which may be a sprocket wheel, such as is shown, adapted to engage the endless chain 5, or it' may be a pulley adapted to engage an endless belt, or other similar device, by which the elevator buckets Gare carried. The elevator thus formed is of the Wellknown typein which the buckets 6 receive their load at the foot of the elevator, carry it upward, and discharge it centrifugally as said'buckets pass around the headwheel 4. The head shaft 1 may be driven in any preferred manner suitable to the conditions under which the machine operates. For purposes of illustrationI have here shown an electric motor '7 having an extension shaft 8 supported in suitable journal bearings 9 attached to the timberslO of the supporting frame-work. Fixed to the extension shaft 8 is a pinion 11 which engages a gear wheel 12 fixed to the head shaft 1 to drive it... The motor 7 may receive its actuating current from any convenient source of electric supply, and may be controlled in any suitable manner, but as such devices are well understood in the art, and as they form no part in the present invention, their description and illustration is not thought to be required at this time.

During the operation of an elevator such as 0 above described, when the electric current by which the motor 7 is actuated is interrupted, the downward pull of the load in the buckets on the ascending strand of the elevator tends to produce reversed revolution of the head shaft 1, causing the loaded buckets to traveldownwardly and discharge their loads at the foot of the elevator, producing a very undesirable congestion even though no definite injury to the apparatus results. Since the electric motor and its connecting gearing offers little or no resistance to such reverse revolution of the head shaft 1, excessive speed might be developed causing serious injury to the apparatus. To prevent such ca tastrophes, Iv have provided a safety lock com- 5 prising a ratchet wheel 13, mounted concentric with the head shaft 1 and anchored against rotation therewith by an arm 14 which is secured to said ratchet Wheel by the bolts 15 and is anchored to the supporting timber 3 by a suitable attachmentlfi. The ratchet wheel 13 is mounted in such relation with the moving parts of the elevator that the ratchet teeth 17 point in the direction of normalrotation of the head wheel 4. Fixed to the head'shaft 1 adjacent the ratchet wheel 5 13 is a disc wheel 18 having an annular flange 19 surrounding and concentric with the ratchet Wheel. On the outer edge of this annular flange 19 is an inwardly projecting flange 20. Supported at spaced intervals in suitable apertures of the flange .20 and disc 18 are a plurality of pivot pins 21 upon which are mounted the pawls 22 adapted to engage the teeth of. the ratchet. The arrangement of parts above described is such that the pawls 22 above the ratchet wheel 13 tend to 0011- tact therewith under the influence of gravity. During operation of the elevator the centrifugal force generated by their rotation'with the head shaft 1 is sufiicient to hold the pawls 22 out of contact with the ratchet wheel 13 thereby avoiding the noise which would be produced by the trailing of thepawls over the teeth of the ratchet. The proportions-of theparts are such, that the annular flange 19 will engage the outer end of the pawls 22 to'limit their outward movement about their pivot pins 21, thus insuringtheir promptly falling into contact with the ratchet wheel 13 when the revolution of the head shaft 1 is interrupted. The number and spacing of the teeth 17 upon the ratchet wheel 13, and. the number and no and having sited yielding movement to absorb spacing of th pawls 22 upon the disc wheel 18, preferably bear such relation to each other that reverse revolution of the shaft 1 through an angle equal to only a fraction of the pitch of the ratchet teeth 17 will cause engagement of a pawl 22, thus insuring the arrest of the shaft 1 before such speed has been attained as will develop sufficient al force to lift the pawls 22 out of engageme; t with the ratchet wheel. The differential or Vernier arrangement of the pawls 22 relative to the to th 17 materially reduces the hock of their engagement, and this shock may be still fur ther reduced by the cushioning effect of a spring 23 included in the anchoring device whereby the arm 14 is secured to the timber 3. As clearly shown in Figure 1, this spring 23 is attached at one end to the timber 3 and at its opposite end to the bolt 16 carried by the arm 14. The bolt 15 operates in an arcuate slot 2% in a block 25 mounted on the timber 3. Thus it will be obvious that the rat het wheel nent member has only a ited yielding movement which is sufficient to aid in cushioning shocks upon reverse tendencies of the shaft 1. When the teeth 17 upon the upper part of the ratchet wheel 13 become worn in service, the bolts 21 may be Withdrawn, the wheel 13 rotated through a suitable angle about the shaft 1 to-bring unworn teeth to the top of the ratchet wheel, and the bolts 21 reinserted to secure he parts in their new relation'.

It is to be understood that I do not limit myself to the precise construction here shown and described, since these devices may be subject to wide variation as to details without departure from the spirit of my invention.

Whatl claim is:

In an apparatus of the class described, the ination with a horizontally extending s aft, of drivi' g ineans adapted to cause said shaft to revolve in one direction, means tending to produce reverse revolution'of said shaft, a stationary ratchet supported concentric with said shaft,

shocks and pawls carried by said shaft adapte to ratchet to prevent reverse revolution of said shaft as and for the purpose set 2. In an apparatus of the class described, the

con bination with a horizontally extending shaft, of driving mean adapted to cause said shaft to revolve in one direction, means tending to produce reverse evolution of said shaft, a ratchet wheel mou; d upon said shaft, resilient means to anchor said ratchet wheelagainst revolution with said shaft, and a pawl carried by said shaft adapted to engage saidratchet wheel to prevent reverse revolution of said shaft as and for the purpose set forth.

3'. In an apparatus of the class described, the combination with a horizontally extending shaft,

of driving means adapted to cause said to revolve in one direction, means tending to produce reverse revolution of said shaft, a ratchet wheel supported concentric with said shaft, means adjustable relative to said ratchet wheel and adapted to prevent its revolution with said shaft, and a awl, carried by said shaft, adapted to engage sa ratchet wheel to prevent reverse revolution of saidshaft as and for the purpose set forth.

. i; Means to arrest reverse rotation of a rotat ing shaft, comprising an abutment member, a cen rifu ally controlled catch member in connection 'th shaft and adapted to engage said abutlnent'meniber to arrest said shaft upon everse tendency of the latter, and means for putting a l ited yielding movement of said a.-.utr1ent mom or upon such engagement.

I-ean to est reverse rotation of a rota ing S1L1E U, comprising an orbitally moving centrifugally controlled. catch member in connection with shaft, 11 abu ent within the orbit of catch member, said catch member being u to gravitate into engagement with said abutment upon a reverse tendency of shaft the latter, and means for permitting elding movement of said abutment ngageinent.

to arrest reverse rotation of a rotatcoin'prising an abutment member, a gally controlled catch member in connection with'said shaft and adapted to engage said abutment member to arrest said shaft upon a reverse tendency of the latter, and means for tting a yielding movement of said abutment member upon such engageznent.

reverse rotation of a rotatan abutment member, a L'ugay controlled catch member in conshaft and adapted to engage mezn'ser to arrest said shaft upon tendency of the latter, and means for a limited movement of said abutment upon such engagement.

sing an abutment member, a .y cont oiled catch member in connecshaft and adapted to engage said aout le t member to arrest said shaft upona reverse tendency of the latter, and resilient means for anchoring said abutment member.

s. Means to arrest reverse rotation of a rotat shaft, comprising an abutment member, a centrifugally controlled catch member in connection with said shaft and adapted to engage saidabutment member to arrest said shaft upon a reverse tendency of the latter, an arm secured to said abutment member, a spring connected to said arm; andmeans for limiting the movement of said arm. i

10. Means to arrest reverse rotation of a horizontally disposedshaft, comprising an adjustable relatively's'tationaryabutment member, and orbitally moving centrifugal controlled catch members in connection with said shaft, at least one of which is adapted to gravitate into engagement with a predeterminedlportion of said abutment member upona reverse tendency of'said shaft to arrest the latter, and said abutment member being adjustable to compensate for wear by said catch in inber;

11. Means to arrest reverse rotation 'of a horizontally disposed shaft, comprising anadjustable relatively stationary ratchet wheel,- orbitally moving centrifugal controlled catch membersin connectionwith said shaft one of which is adapted to gravitate into engagement with a predetermined portion of said ratchet wheel upon a reverse tendency of said shaft to arrest the latter,'and said ratchet "wheel being adjustable in a orbital path to compensatefor wear thereon by said catch member.

12. Means to arrest reverse rotation of a horizontally disposed shaft, comprising an adjustable relatively stationary ratchet fwheel, orbitally moving, centrifugal controlled catch members in connection with said shaft one of which is'adaptedto gravitateinto engagement with a predetermined portion of said ratchet wheel upon reverse tendency of said shaft to a1 1o arrest reverse rotation of a rotat rest the latter, said catch members having a Vernier arrangement relative to the teeth of said ratchet wheel, and said ratchet wheel being adjustable to compensate for wear thereon by said catch member.

13. Means to arrest reverse rotation of a horizontally disposed shaft, a relatively stationary member, a ratchet wheel adjustably connected to said member, orbitally moving centrifugal controlled catch members, in connection with said shaft, one of said catch members being adapted to gravitate into engagement with a predetermined portion of said ratchet Wheel upon reverse tendency of said shaft to arrest the latter, and said ratchet wheel being adjustable relative to said stationary member to compensate or wear upon the ratchet Wheel occasioned by said catch members.

l4. lvleans to arrest reverse rotation of a horizontally disposed shaft comprising an abutment member, a centrifugally controlled catch member in connection with said shaft and adapted to engage said abutment member to arrest said shaft upon a reverse tendency of'the latter, a slotted member, an arm secured to said abutment member, and having means operating in said slottedmember, and spring means for retaining said arm in predetermined relation to said slotted member.

15. Means to arrest reverse rotation of a horizontally disposed shaft comprising an abu ment member, a centrifugally controlled catch member in connection with said shaft and adapted to engage said abutment member to arrest said shaft upon a reverse tendency of the latter, a stationary member having a slot, an arm secured to said abutment member and having a projection operating in said slot, and spring means connected to said arm and said stationary slotted member for retaining the arm in predetermined relation to the latter.

16. Means .to arrest reverse rotation of a horizontally disposed shaft comprising a relatively stationary abutment disc loosely mounted upon said shaft, said disc having its periphery equipped with ratchet teeth, means adjustably associated with said disc'for retaining the same relatively stationary upon said shaft, a wheel fixed to said shaft and having an annular flange overlapping said abutment disc, and pawls car-l ried by said wheel beneath said flange for engagement with the ratchetteeth of said disc.

1'7. Means to arrest reverse rotation of 'a horizontally disposed shaft comprising a stationary abutment member, a carrier rotatable with the shaft, centrifugally controlled catch members mounted on said carrier and adapted to gravitate into engagement withthe abutment memberupon reverse tendency of said shaftto arrest the latter, said catch members being arranged with respect to the abutment member whereby at least one of said catch members will engage said abutment member in any position of 100 said carrier.

18. Means to arrest reverse rotation of a horizontally disposed shaft comprising a relatively stationary abutment member free of said shaft, means associated with said abutment member for preventing movement ofthe same with respect to said shaft, an element fixed to said shaft and-having an annular flange overlapping said abutment member, and pawls car ried by said element beneath said flange for engagement with said abutment member.

STANLEY M. MERCIER. 

